1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * kexec_file for arm64 4 * 5 * Copyright (C) 2018 Linaro Limited 6 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org> 7 * 8 * Most code is derived from arm64 port of kexec-tools 9 */ 10 11 #define pr_fmt(fmt) "kexec_file: " fmt 12 13 #include <linux/ioport.h> 14 #include <linux/kernel.h> 15 #include <linux/kexec.h> 16 #include <linux/libfdt.h> 17 #include <linux/memblock.h> 18 #include <linux/of_fdt.h> 19 #include <linux/random.h> 20 #include <linux/slab.h> 21 #include <linux/string.h> 22 #include <linux/types.h> 23 #include <linux/vmalloc.h> 24 #include <asm/byteorder.h> 25 26 /* relevant device tree properties */ 27 #define FDT_PROP_KEXEC_ELFHDR "linux,elfcorehdr" 28 #define FDT_PROP_MEM_RANGE "linux,usable-memory-range" 29 #define FDT_PROP_INITRD_START "linux,initrd-start" 30 #define FDT_PROP_INITRD_END "linux,initrd-end" 31 #define FDT_PROP_BOOTARGS "bootargs" 32 #define FDT_PROP_KASLR_SEED "kaslr-seed" 33 #define FDT_PROP_RNG_SEED "rng-seed" 34 #define RNG_SEED_SIZE 128 35 36 const struct kexec_file_ops * const kexec_file_loaders[] = { 37 &kexec_image_ops, 38 NULL 39 }; 40 41 int arch_kimage_file_post_load_cleanup(struct kimage *image) 42 { 43 vfree(image->arch.dtb); 44 image->arch.dtb = NULL; 45 46 vfree(image->arch.elf_headers); 47 image->arch.elf_headers = NULL; 48 image->arch.elf_headers_sz = 0; 49 50 return kexec_image_post_load_cleanup_default(image); 51 } 52 53 static int setup_dtb(struct kimage *image, 54 unsigned long initrd_load_addr, unsigned long initrd_len, 55 char *cmdline, void *dtb) 56 { 57 int off, ret; 58 59 ret = fdt_path_offset(dtb, "/chosen"); 60 if (ret < 0) 61 goto out; 62 63 off = ret; 64 65 ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR); 66 if (ret && ret != -FDT_ERR_NOTFOUND) 67 goto out; 68 ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE); 69 if (ret && ret != -FDT_ERR_NOTFOUND) 70 goto out; 71 72 if (image->type == KEXEC_TYPE_CRASH) { 73 /* add linux,elfcorehdr */ 74 ret = fdt_appendprop_addrrange(dtb, 0, off, 75 FDT_PROP_KEXEC_ELFHDR, 76 image->arch.elf_headers_mem, 77 image->arch.elf_headers_sz); 78 if (ret) 79 return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL); 80 81 /* add linux,usable-memory-range */ 82 ret = fdt_appendprop_addrrange(dtb, 0, off, 83 FDT_PROP_MEM_RANGE, 84 crashk_res.start, 85 crashk_res.end - crashk_res.start + 1); 86 if (ret) 87 return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL); 88 } 89 90 /* add bootargs */ 91 if (cmdline) { 92 ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline); 93 if (ret) 94 goto out; 95 } else { 96 ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS); 97 if (ret && (ret != -FDT_ERR_NOTFOUND)) 98 goto out; 99 } 100 101 /* add initrd-* */ 102 if (initrd_load_addr) { 103 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START, 104 initrd_load_addr); 105 if (ret) 106 goto out; 107 108 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END, 109 initrd_load_addr + initrd_len); 110 if (ret) 111 goto out; 112 } else { 113 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START); 114 if (ret && (ret != -FDT_ERR_NOTFOUND)) 115 goto out; 116 117 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END); 118 if (ret && (ret != -FDT_ERR_NOTFOUND)) 119 goto out; 120 } 121 122 /* add kaslr-seed */ 123 ret = fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED); 124 if (ret == -FDT_ERR_NOTFOUND) 125 ret = 0; 126 else if (ret) 127 goto out; 128 129 if (rng_is_initialized()) { 130 u64 seed = get_random_u64(); 131 ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed); 132 if (ret) 133 goto out; 134 } else { 135 pr_notice("RNG is not initialised: omitting \"%s\" property\n", 136 FDT_PROP_KASLR_SEED); 137 } 138 139 /* add rng-seed */ 140 if (rng_is_initialized()) { 141 u8 rng_seed[RNG_SEED_SIZE]; 142 get_random_bytes(rng_seed, RNG_SEED_SIZE); 143 ret = fdt_setprop(dtb, off, FDT_PROP_RNG_SEED, rng_seed, 144 RNG_SEED_SIZE); 145 if (ret) 146 goto out; 147 } else { 148 pr_notice("RNG is not initialised: omitting \"%s\" property\n", 149 FDT_PROP_RNG_SEED); 150 } 151 152 out: 153 if (ret) 154 return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL; 155 156 return 0; 157 } 158 159 /* 160 * More space needed so that we can add initrd, bootargs, kaslr-seed, 161 * rng-seed, userable-memory-range and elfcorehdr. 162 */ 163 #define DTB_EXTRA_SPACE 0x1000 164 165 static int create_dtb(struct kimage *image, 166 unsigned long initrd_load_addr, unsigned long initrd_len, 167 char *cmdline, void **dtb) 168 { 169 void *buf; 170 size_t buf_size; 171 size_t cmdline_len; 172 int ret; 173 174 cmdline_len = cmdline ? strlen(cmdline) : 0; 175 buf_size = fdt_totalsize(initial_boot_params) 176 + cmdline_len + DTB_EXTRA_SPACE; 177 178 for (;;) { 179 buf = vmalloc(buf_size); 180 if (!buf) 181 return -ENOMEM; 182 183 /* duplicate a device tree blob */ 184 ret = fdt_open_into(initial_boot_params, buf, buf_size); 185 if (ret) 186 return -EINVAL; 187 188 ret = setup_dtb(image, initrd_load_addr, initrd_len, 189 cmdline, buf); 190 if (ret) { 191 vfree(buf); 192 if (ret == -ENOMEM) { 193 /* unlikely, but just in case */ 194 buf_size += DTB_EXTRA_SPACE; 195 continue; 196 } else { 197 return ret; 198 } 199 } 200 201 /* trim it */ 202 fdt_pack(buf); 203 *dtb = buf; 204 205 return 0; 206 } 207 } 208 209 static int prepare_elf_headers(void **addr, unsigned long *sz) 210 { 211 struct crash_mem *cmem; 212 unsigned int nr_ranges; 213 int ret; 214 u64 i; 215 phys_addr_t start, end; 216 217 nr_ranges = 1; /* for exclusion of crashkernel region */ 218 for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 219 MEMBLOCK_NONE, &start, &end, NULL) 220 nr_ranges++; 221 222 cmem = kmalloc(sizeof(struct crash_mem) + 223 sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL); 224 if (!cmem) 225 return -ENOMEM; 226 227 cmem->max_nr_ranges = nr_ranges; 228 cmem->nr_ranges = 0; 229 for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 230 MEMBLOCK_NONE, &start, &end, NULL) { 231 cmem->ranges[cmem->nr_ranges].start = start; 232 cmem->ranges[cmem->nr_ranges].end = end - 1; 233 cmem->nr_ranges++; 234 } 235 236 /* Exclude crashkernel region */ 237 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); 238 239 if (!ret) 240 ret = crash_prepare_elf64_headers(cmem, true, addr, sz); 241 242 kfree(cmem); 243 return ret; 244 } 245 246 int load_other_segments(struct kimage *image, 247 unsigned long kernel_load_addr, 248 unsigned long kernel_size, 249 char *initrd, unsigned long initrd_len, 250 char *cmdline) 251 { 252 struct kexec_buf kbuf; 253 void *headers, *dtb = NULL; 254 unsigned long headers_sz, initrd_load_addr = 0, dtb_len; 255 int ret = 0; 256 257 kbuf.image = image; 258 /* not allocate anything below the kernel */ 259 kbuf.buf_min = kernel_load_addr + kernel_size; 260 261 /* load elf core header */ 262 if (image->type == KEXEC_TYPE_CRASH) { 263 ret = prepare_elf_headers(&headers, &headers_sz); 264 if (ret) { 265 pr_err("Preparing elf core header failed\n"); 266 goto out_err; 267 } 268 269 kbuf.buffer = headers; 270 kbuf.bufsz = headers_sz; 271 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; 272 kbuf.memsz = headers_sz; 273 kbuf.buf_align = SZ_64K; /* largest supported page size */ 274 kbuf.buf_max = ULONG_MAX; 275 kbuf.top_down = true; 276 277 ret = kexec_add_buffer(&kbuf); 278 if (ret) { 279 vfree(headers); 280 goto out_err; 281 } 282 image->arch.elf_headers = headers; 283 image->arch.elf_headers_mem = kbuf.mem; 284 image->arch.elf_headers_sz = headers_sz; 285 286 pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 287 image->arch.elf_headers_mem, headers_sz, headers_sz); 288 } 289 290 /* load initrd */ 291 if (initrd) { 292 kbuf.buffer = initrd; 293 kbuf.bufsz = initrd_len; 294 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; 295 kbuf.memsz = initrd_len; 296 kbuf.buf_align = 0; 297 /* within 1GB-aligned window of up to 32GB in size */ 298 kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) 299 + (unsigned long)SZ_1G * 32; 300 kbuf.top_down = false; 301 302 ret = kexec_add_buffer(&kbuf); 303 if (ret) 304 goto out_err; 305 initrd_load_addr = kbuf.mem; 306 307 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 308 initrd_load_addr, initrd_len, initrd_len); 309 } 310 311 /* load dtb */ 312 ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb); 313 if (ret) { 314 pr_err("Preparing for new dtb failed\n"); 315 goto out_err; 316 } 317 318 dtb_len = fdt_totalsize(dtb); 319 kbuf.buffer = dtb; 320 kbuf.bufsz = dtb_len; 321 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; 322 kbuf.memsz = dtb_len; 323 /* not across 2MB boundary */ 324 kbuf.buf_align = SZ_2M; 325 kbuf.buf_max = ULONG_MAX; 326 kbuf.top_down = true; 327 328 ret = kexec_add_buffer(&kbuf); 329 if (ret) 330 goto out_err; 331 image->arch.dtb = dtb; 332 image->arch.dtb_mem = kbuf.mem; 333 334 pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 335 kbuf.mem, dtb_len, dtb_len); 336 337 return 0; 338 339 out_err: 340 vfree(dtb); 341 return ret; 342 } 343